My bartender is a friend of mine, who volunteered her services for my reception. I offered to pay her, and she refuses to accept any money from me, and claims that she will just work for the tips from the guests. (I intend to tip her generously for her time with or without her knowing) but do people generally tip bartenders at a wedding? Is it tacky for her to have a tip jar? We are providing a full open bar for our guests.